California is in the middle of one of theworst droughts in recorded history. Things have gotten so serious that this Thursday the state legislature attempted to ease the pain by passing a $687 million relief plan for drought-stricken communities. Even NASA has stepped in to lend its space- and sky-based science, hoping to assist the state's Department of Water Reclamation with deciding where to dole out its water reserves and identify the areas in most need of aid.

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Jeanine Jones, interstate water resources manager at California's DWR, says that for water managers who operate the state's dams and aqueducts, understanding the extent of the current drought is very important. "We make lots of different kinds of decisions about how to operate facilities, to supply water, to minimize flood risk, and to do long-term water planning for the entire state," she says.

Here's a look at the NASA research programs helping California better understand the drought:

Airborne Snow Observatory

Snowpack in the Sierra Nevada provides 60 to 80 percent of California's freshwater. To find out how much water the peaks hold, scientists on the ground plunge tubes into the snow and weigh them to determine their water equivalent. They also bury snow pillows—panels filled with an antifreeze solution that measure the weight of snow as it falls on top of them. But snow pillows melt out of the snowpack early in the season and "as soon as they melt out,water managers go blind," said the Jet Propulsion Laboratory's Tom Painter at a press conference this week.

NASA will begin flying its Airborne Snow Observatory at the end of March. The plane uses scanning lidar (a laser that measures light reflection) to determine how much sunlight is reflecting off the snow, a statistic that helps scientists determine how quickly it will melt. The lidar also helps the team determine how deep the snow is. Taken together, these stats give scientists an unprecedented understanding of the total amount of snow.

With the help of JPL supercomputers, scientists can take data from the observatory, map it, and turn it around for use by water managers in just 24 hours. "Last year we started flying in Tuolumne River basin [in Yosemite]," Painter said. "We were mapping the snowpack in about 1.5-meter resolution. It's a detail of the snowpack that we've never had."

Says DWR's Jones: "Our ground-based network can't cover the entire watershed. They don't have as much coverage at higher elevations where it's difficult to put these things. The observatory allows us to improve the information that we put in our runoff models."

Satellites to Track Fallow Land

During normal seasons, farmers intentionally leave some land unseeded to allow the soil a period of recovery. This fallow land, however, takes on an entirely different meaning during drought. Farmers are forced to prioritize crops differently when they can't irrigate all their fields. Understanding the full extent of fallow farmland can help the state determine areas hardest hit by the drought.

There is currently information available about land that has been left fallow, but because that data can influence the market, the USDA doesn't share field maps until after the season has ended. So NASA is turning its satellites toward California farmland. With help from the U.S. Geological Survey, its scientists are studying images to determine crop development (or lack thereof) down to the level of individual fields.

In April, they will begin releasing estimates about water use in California's Central Valley. This information will allow the state to determine where lack of planting is causing reduced farm incomes, lower sales, and unemployment. Jones says areas with high rates of fallow land also face food shortages.

Radar to Find Groundwater Levels

Groundwater is crucial to agriculture but difficult to track. In many cases, understanding how much water is in a given area involves studying individual wells on private property—not exactly the most efficient system. Thankfully, NASA spent four years, from 2007 to 2011, training satellite radar on the San Joaquin Valley to track the rise and fall of the ground throughout the state.

Surface deformation points to areas where underground water exists, and shows the extent of water pumping. To understand the deformation, researchers at JPL used interferometric synthetic aperture radar (InSAR), which detects changes in land deformation down to the inch by shooting radar waves at the ground and then returning to the same area later to measure the change in wavelengths. They pinpointed hot spots where deformation is the worst, indicating that DWR needs to take action to reduce groundwater pumping. The InSAR team is now working on developing a system they can give to DWR that will allow them to continually monitor the surface subsistence of the state into the future.

"We can go to people and say: ‘You've created a local hot spot and you need to figure out how to fix that,'" Jones says. "Otherwise you'll be damaging water supply and flood-control infrastructure."